Scientists Track Microbe Transmission from Mother to Infant

BY Jordan Rosenfeld

January 26, 2017

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There's strong evidence that babies inherit their gut microbiomes from their mothers, but it's been unclear if the microbiome transmission takes place in the womb, at birth, or after birth; there are likely multiple paths of transmission unfolding over time. Microbial diversity is crucial to building up many functions, including the immune system, digestion, and even combating complex diseases. Recent research has found a connection between our gut microbiomes and our mental health as well.

However, studying the direct transmission of these microbes and identifying the strains of bacteria has been difficult until recently. Now researchers at the Centre for Integrative Biology at the University of Trento (UoT), Italy, have developed methods to track this microbial “vertical transmission,” as it’s called, and made some new discoveries in their methodological study, published in mSystems, an open access journal from the American Society for Microbiology.

“We know the infant increases [its] microbial diversity after birth and will continue doing so until being an adult,” senior study author Nicola Segata, an assistant professor at UoT, tells mental_floss. “We needed to understand from where microbes are coming in the first place.”

Many microbes are likely transmitted from mother to infant at birth and just after birth through direct contact with the birth canal, the skin, and through breast milk, but they had not yet done thorough investigations of the strains of bacteria to corroborate this. This is also important in the case of identifying the transmission of microbes that are dangerous to the infant’s health, such as Group B Streptococcus, which can cause an infection, and even death, in infants.

Segata explains, “Our contribution is really tracking which bacteria are moving from mother to infant. It was already known that certain microbes were present in the mother and infant but each had a different strain of, say, E. coli or Bifidobacterium. We looked to see if mothers and infants had the same strain of E. coli, or if it was a different strain from other infants and mothers.”

Taking fecal and breast milk samples from five mother-infant pairs when the infants were 3 months, 10 months, and, for one pair, at 16 months of age, Segata and his team used a technique called shotgun metagenomic sequencing of 24 microbiome samples of either fecal or breastmilk samples to determine which microbes were present. (This technique makes it possible to sample genes from all organisms in a sample.) Then they used another method known as metatranscriptomics to study RNA in fecal samples to identify active microbes.

“Each mother and infant pair had different strains of bacteria, but when you match each mother and her infant, they have the same strain, so this is strong evidence of the strain coming from the mother,” Segata says.

Another important discovery, Segata says, is that “these strains acquired from the mother are also active in the infant gut, they are alive. It’s important that the strains moving from mother to infant are active, colonizing.”

While this study allowed them to say confidently, “We can track microbe transmission from mother to infant,” Segata says their next study will allow them to identify which microbes, and whether they will survive in the infant gut.

In what must be some kind of record for soliciting infant head cozies, the Oklahoma State Department of Health (OSDH) has put out an open call for hand-knitted baby hats. And not just any baby hats—they have to be purple.

The campaign is part of an effort to raise awareness of Shaken Baby Syndrome, a form of abusive head trauma that's a damaging parental response to excessive crying and can result in serious brain injury. The effort, dubbed "Click for Babies" after the sound knitting needles make, is intended to highlight the potential hazards of improper infant care.

Why purple? Because the National Center for Shaken Baby Syndrome refers to an infant’s period of prolonged crying as the PURPLE period. The word is an acronym for reminders about the syndrome: L, for example, stands for Long-Lasting. Babies can cry for five hours a day, up to four months of age.

Potential donors should choose a washable, soft yarn, with the hat standing 4 to 6 inches high. Due to potential choking hazards, decorations are not recommended.

OSDH will be collecting caps through October 1 and the knitwear will be distributed to birthing hospitals and public health facilities along with a booklet on Shaken Baby Syndrome. If you’d like to donate a hat, you can mail it to any one of three addresses listed on the state’s web site. The program is hoping to receive 5000 hats for the cause. You can also check out the Click for Babies website to see if the campaign is being promoted in your state.

Elisabeth Anderson-Sierra makes much, much more breast milk than your average mother. So the Beaverton, Oregon, resident has become a major donor to milk banks, giving her milk away to babies in need all over the country, according to Portland ABC affiliate KATU.

Anderson-Sierra has what’s called Hyper Lactation Syndrome, meaning that her body produces far more than her 6-month-old baby can use. Most nursing mothers produce in the range of 15 to 30 ounces of breast milk a day, but she produces around 225 ounces (1.7 gallons). That's a lot of extra milk.

For many mothers, Hyper Lactation Syndrome is a major problem, not an opportunity for charity. It makes most women’s breasts feel overfull all the time, and can lead to plugged ducts and leaking between feedings. It can also cause issues for nursing babies, who can develop colic. Pumping more isn’t usually the answer—that tells the body that the milk is being used, and to produce more—but Anderson-Sierra seems to see her overproduction as the solution to a problem, rather than a problem in itself.

“Breast milk is liquid gold,” she told KATU. “It should never be thrown away.” (It is, in fact, a miraculously versatile fluid, and the recommended food source for babies under 6 months old.) Anderson-Sierra has two full-sized freezers stacked with bags and bags of breast milk in her Oregon home. She donates them to a milk bank that tests her milk and sends it out nationwide, including for use in feeding premature babies in hospitals. The bank reimburses her a dollar an ounce, which she uses to pay for her freezers and to buy more bags and sanitation kits.

Anderson-Sierra spends hours out of her day pumping breast milk, which sounds utterly exhausting. Those preemies in the NICU are grateful for her time, surely. It's a lot more generous than most of us would be with our bodies.